1. Field of the Invention
The present invention relates to pneumatic particle transport systems, for example systems used to discharge particulate material from transport vehicles to a storage facility, and more particularly to a pre-screening element for such systems.
2. Description of the Prior Art
Historically, pneumatic transport systems have been used to empty transport tanks filled with particulate material, such as flour, sugar, plastic pellets or other fine material, into larger storage containers. A screening filter is traditionally used to filter the material before it enters the storage container. The particulate material will tend to clump together when the relative humidity of the ambient air is high enough, so called xe2x80x9cchokingxe2x80x9d, making the discharge operation difficult with frequent stops to clean the discharge hoses and other equipment. Frequently, the operator bangs on the discharge equipment, such as hoses and hoppers, with a rubber hammer to facilitate the flow of material.
It is an object of the invention to provide a pre-screening element which breaks up lumps in the particulate material so that there is little or no clogging of the hoses, nozzles, couplings or filter screens of the discharge system due to lumping of material due to moisture or similar.
Another object of the invention is to provide a pre-screening adapter, utilizing the pre-screening element of the invention, attachable to a discharge coupling on a transport vehicle at one end of the adapter and to a discharge hose at the other end of the adapter. Alternatively, the adapter is attachable to the discharge hose at one end of the adapter and to an inlet coupling of a storage tank at the other end of the adapter.
Still a further object of the invention is to provide a discharge system for handling powdered solids comprising a transport container, a pneumatic discharge system having a fan/blower connected to said container via a first duct and a discharge duct connected to said transport container and a pre-screening adapter according to the invention.
In the invention, a pre-screening element for use with pneumatic discharge systems for transport of powdered material comprises
a housing having an inlet and an outlet;
a first vane array, having a plurality of strip-shaped first vanes arranged inside the housing and spaced apart with respect to a longitudinal axis of the housing, each individual vane of the plurality of first vanes being substantially parallel to other vanes of the first vane array and having a long edge facing the inlet;
a second vane array, having a plurality of strip-shaped second vanes arranged inside the housing and spaced apart with respect to a longitudinal axis of the housing, each individual vane of the plurality of second vanes being substantially parallel to other vanes of the second vane array and having a long edge facing the inlet, a longitudinal axis of the first vanes being arranged at an angle to a longitudinal axis of the second vanes.
The angle is preferably between 5 and 90 degrees, most preferably 45 degrees.
Preferably, the housing is generally cylindrical.
The plurality of first vanes are advantageously arranged in a common plane generally perpendicular to the longitudinal axis of the housing. The plurality of second vanes are similarly also advantageously arranged in a common plane generally perpendicular to the longitudinal axis of the housing.
A pre-screening adapter, according to the invention, comprises a length of pipe having a male coupling attached at a first end and a female coupling attached at a second end, and a pre-screening element arranged inside the pipe, the element being as defined above.
A discharge system, according to the invention, comprises a transport container mounted on a vehicle, a pneumatic discharge system having a fan connected to the container via a first duct and a discharge duct connected to the transport container for discharging material pressurized in the transport container by the fan, and a pre-screening adapter as defined above.
Further features of the invention will be described or will become apparent in the course of the following detailed description.